The overall goal of this project is to investigate the effect of hearing impairment on auditory perceptual organization. Obtained results may have important implications for refining and differentiating the concept of auditory processing, which is a primary contributor to communicative disorder. Subjects will represent both cross-sectional and longitudinal groups. Cross- sectional groups will consist of 200 children, 100 normal and 100 hearing-impaired, from 3 through 7 years of age. Longitudinal groups will consist of 10 normal and 10 hearing-impaired children, followed from either 3 to 6 years or from 4 to 7 years of age. Our approach to studying auditory perceptual organization will focus on determining how the auditory and semantic dimension of speech are combined in perceptual processing by children. To investigate this issue, a pediatric selective attention task that utilizes both conflict and congruence between auditory and semantic speech dimensions has been constructed. The task is a pediatric auditory analog of the well-known adult, visual procedure, termed the "Stroop" test. We predict that systematic variation in the semantic dimension of speech will interact with processing of the auditory dimension in accordance with the "analyzer" model of selective attention for multidimensional signals. Pilot data on the newly developed pediatric auditory "Stroop" task indicated that normal-hearing and severely hearing-impaired children exhibit different patterns of interaction between the auditory and semantic dimensions of speech. Further data on a large series of normal- hearing and hearing-impaired subjects, representing a broad range of different types and degrees of hearing impairment, will elaborate characteristics of this pattern of interaction. Results of the proposed project should provide knowledge about 1) the development of normal perceptual organization, an important aspect of perceptual processing, 2) the extent to which development of perceptual organization is influenced by abnormal experience with auditory stimulation and 3) the automaticity of semantic processing young children. Better understanding of normal perceptual development may have important clinical implications for the design of remediation programs for children with developmental abnormalities in perceptual processing. Better understanding of the effect of hearing impairment on perceptual organization may be important in improving our ability to promote the development of normal communication skills in hearing-impaired children.